Nozzles for fluidized bed vessel construction plate

ABSTRACT

An improved nozzle is provided for the constriction plate in a fluidized bed type of heat transfer apparatus.

United States Patent [191 Erisman 1 Jan. 9, 1973 [54] NOZZLES FORFLUIDIZED BED 1,873,594 8/1932 Johnson ..210/277 VESSEL CONSTRUCTIONPLATE 2,378,157 6/1945 Ramseyer et a1. ..34l57 A 2,389,133 11/1945Brassert et al. 34/57 A X [75] Maurice Erisman Oak Park 3,040,439 6/1962Frost .34/57 A Assignee; Corporation San Jose 3,197,286 Farkas et a1 S X3,298,793 1/1967 Mallison et a1..... 34/57 A UX Flledi 8, 1970 3,494,0462/1970 Harkreader ..34/57 A x [2]] Appl' 70378 FOREIGN PATENTS ORAPPLICATIONS US CL I 34/57 A 377,433 7/1932 Great Britain ..110/75 B[51] Int. Cl. ..F26b 3/16, F26b 17/00 [58] Field of Search ..34/57 A, 57E, 57, 10; fi' O 23 2 3 S, 2 4 3 2 A; 210/277; Assistant Exammer-W. C.Anderson 239/DIG l 2 7 271 552 Attorney-F. W. Anderson and C. E. Tripp[56] Rgferences Cited 1 1 ABSTRACT UNITED STATES PATENTS An improvednozzle is provided for the constriction plate in a fluidized bed type ofheat transfer apparatus. 1,151,348 8/1915 Dunster ..l10/175R 1,713,4005/1929 Schaperjahn ..1 10/75 B 3 Claims, 10 Drawing Figures PATENTEUJAH9 I975 JLMW (2.6%

PATENIEDJAM ems I 3,708,887

SHEET 2 OF 2 NOZZLES FOR FLUIDIZED BED VESSEL CONSTRUCTION PLATEBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates generally to heat transfer vessels of the fluidized bed type andmore particularly to new and improved nozzles located in thehorizontally positioned constriction plate for feeding gases into a bedof particulate bulk material on the constriction plate for fluidizingsuch material. The nozzles are adjustable, have inclined orifices whichprevent the entrance of material and the resulting direction of thegases tends to prevent build up of the material adjacent to the nozzlewhich might otherwise become overheated and ignite if combustible.

2. Description of the Prior Art A nozzle for a constriction plate in afluidized bed apparatus is disclosed in the US Pat. No. 2,841,476 issuedto B. S. Dalton on July 1, 1958. This vertical nozzle has horizontallyelongated passageways for the fluidizing gases which are of a lengthgreater than the distance to which the solids would reach in thepassageway under the normal angle of repose of the defluidized solids sothat sifting of these solids into the main body of the nozzle isprevented.

Another nozzle for a gas diffusing plate in a solids fluidizing vesselis disclosed in US. Pat. No. 3,040,439 issued to W. G. Frost on June 26,1962. This vertical nozzle includes a conical head with its perimeteroverhanging the shank portion to prevent the solids from falling intothe windbox. This nozzle also has an annu lar array of radial holesthrough the shank of the nozzle and under the conical head, whose axesare downwardly inclined.

In US. Pat. No. 3,370,938, issued to Newman et al. on Feb. 27, 1968,tuyeres for a fluidizing vessel are disclosed that use a tubular memberclosed at the top and that have gas distributing nozzles which areinclined downwardly. Overcaps are also provided on the bottom of thetubular member, which have orifices for controlling the flow offluidizing gas.

A further type of nozzle for a fluid bed processor is disclosed in [1.5.Pat. No. 3,495,336, issued to Gecewich et al. on Feb. 17, 1970. Thisunit comprises a round headed pin having a large diameter washer underthe head. This assembly is mounted in an aperture in the constrictionplate, the diameter of the aperture being approximately twice thediameter of the pin. The assembly is constrained from lifting completelyout of the aperture under the flow of gas by a horizontally mounted pinthrough the lower end of the body of the round headed pin under theconstriction plate. The pin and washer assembly rises above the level ofthe constriction plate under the pressure of the flowing gas and thewasher diameter is sufficiently large that due to the normal angle ofrepose of the solids around the periphery of the washer, the solids donot reach the aperture and are thus prevented from falling into theplenum chamber. When the gas flow is stopped, the pin-washer assemblydrops back onto the constriction plate to close the aperture in theplate and thus seal this opening from the solids.

SUMMARY OF THE INVENTION In a heat transfer vessel of the fluidized bedtype a horizontal constriction plate or grate is generally provided onwhich the bed of bulk material rests. The constriction plate provides acontrolled pressure drop of gases flowing from below the constrictionplate through the bed of material. This flowing gas has to bedistributed and diffused uniformly throughout the bed to properlyfluidize the material so that the particles of material are completelysurrounded by the gas. Material characteristics, such as grain size,amount of moisture, and particle size distribution, all affect thevelocity of the gas required to obtain the proper turbulence to separateand suspend the particles so that efficient heat transfer can takeplace. When fluidized, the material above the constriction plate actslike a fluid and flows in a generally horizontal path directly above theplate. The bed depth is controlled by a discharge weir and the amount offluidization. When the material flows over the weir, it is collected ina chute and passes through an air-lock gate to a conveyor or other meansof discharge. The gases above the bed pass through a dust collector,where the fines are separated to a fan and are then generally dischargedinto the atmosphere.

This invention relates particularly to the type of nozzles used in theconstriction plate. The nozzle itself comprises a vertical tubularmember mounted in the constriction plate and a compact cap member sothat nozzles may be placed relatively close together withoutinterference. The cap member contains a series of orifices around itsperiphery, each orifice having a downwardly inclined axis andcommunicating with the central internal passage of the vertical tubularmember. The inclined orifices direct the flowing gas around the base ofthe tubular member to fluidize the material in this area, as well asabove, so that buildup of material at the tube base is prevented. In thecase of a combustible material, such as fine soft coal, this gasmovement at the base of the nozzle will further prevent the otherwisestationary material from overheating and burning. The cap member isfurther easily removed, for cleaning or changing to obtain orifices of adifferent quantity or inclination of their axes, without disturbing thevertical tubular member or permitting material to fall into theapertures in the constriction plate. The tubular member, in thepreferred embodiment, is further constructed so that the height of theorifices above the constriction plate is adjustable and can be easilyvaried to obtain the maximum cleaning effect around its base and toobtain maximum efficiency of fluidization.

Accordingly, it is an important object of the present invention toprovide an improved nozzle for a fluid-bed heat transfer vessel.

Another object of the invention is to provide a nozzle that isrelatively compact in size so that multiple nozzles may be placed closetogether without interference.

Another object of the invention is to provide a nozzle in which theorifices are located in an easily removable member for quicksubstitution of other units having different sizes of apertures, anglesof inclination of the orifices, or quantity of orifices withoutdisturbing the member in the constriction plate.

A further object of the invention is to provide a nozzle in which thevertical member in the constriction plate is adjustable so that theheight of the orifices may be varied or adjusted to obtain maximumfluidization and cleaning of the material around the base of the nozzle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagramatic and schematicillustration, with certain portions in section, of a heat transferapparatus of the fluidized bed type that is particularly useful fordrying the bulk material being processed.

FIG. 2 is a plan view of the constriction plate taken along line 22 inFIG. 1.

FIG. 3 is a fragmentary elevational view of the constriction plate ofFIG. 2 showing one nozzle in position.

FIG. 4 is an enlarged elevational view of one nozzle in the constrictionplate surrounded by the bed of material, with flow lines indicating theflow of gas.

FIG. 5 is a plan view of one embodiment of a nozzle of the invention.

FIG. 6 is a cross-sectional view of the nozzle taken along line 66 inFIG. 5.

FIG. 7 is a plan view of a second embodiment of a nozzle of theinvention.

FIG. 8 is a cross-sectional view of the nozzle taken along line 77 ofFIG. 7.

FIG. 9 is a side elevational view of a third embodiment of a nozzle ofthe invention.

FIG. 10 is a cross-sectional view of the nozzle taken along line 9-9 ofFIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 there is shown a heattransfer apparatus of the type in which the apparatus of the presentinvention is used. In particular there is illustrated a dryer of thefluidized bed type in which a constriction plate 11 is used to diffuseand control hot air being fed into the bed of particulate material 12.An air heater 13 provides hot air, which passes through a plenum chamber14 and is forced through the constriction plate and the bed of materialin a drying chamber 15. The hot gases, dust, and fines are pulledthrough a dust collector 16 by a fan 17 and are then exhausted to theatmosphere. The bulk material to be dried is stored in a hopper l8 andis fed by a screw feeder 19 onto the constriction plate 11, which has aweir 20 to control the depth of the bed. The constriction plate containsa series of nozzles of the present invention, to be described later, andthe hot gas flowing through the nozzles fluidizes the bed of material sothat the solid particles are separated and suspended. In this state, thefluidized material behaves like a liquid and flows in a generallyhorizontal path directly above the constriction plate 11 and over theweir 20 into a discharge chute 26. The discharge chute has a rotaryvalve or air-lock 27 to control the material flow onto a dischargeconveyor 28.

While the illustrative example shows a single constriction plateconstruction for drying, it is to be understood that the presentinvention can be equally well used as a cooler or in a combinationdryer-cooler in which dual constriction plates are used. In the latter,cool air is fed through the lower plate; while hot air is fed into thechamber between the two plates and through the upper plate. The materialis first dried on the upper plate and is then fed onto the lower platefor cooling before discharge.

FIGS. 2 and 3 illustrate the constriction plate 11, which has a seriesof closely spaced staggered holes in which nozzles 25 are mounted.Nozzles 25, as shown in FIG. 4, project upward into the bed of material12 and have orifices 29 which direct the flow of gas downwardly onto theconstriction plate 1 1, the gas then flowing upwardly through the bed ofmaterial 12. The quantity and spacing of the nozzles will be dependentupon the area of the constriction plate and the type and condition ofthe material'being processed so as toobtain the desired evendistribution of gas to properly fluidize the material.

The preferred embodiment of nozzle 25, as shown in FIGS. 5 and 6,comprises a tubular member 30, a cap member 31, and an adjusting nut 32.As shown, the tubular member 30 is externally threaded with a straightscrew thread 33 for most of its length but has a tapered pipe thread 34at its top end. The holes 35 in the constriction plate 11 containmatching straight-threads for securing the lower end of the tubularmember therein. The nut 32 locks the tubular member 30 at apredetermined height or degree of rotation. It is, of course, alsopossible to eliminate the threads in plate 11 and lock the tubularmember 30 in the constriction plate by using two nuts 32, one being ontop of plate 11 as shown and a second nut being under plate 11. The capmember 31 is a short tubular piece closed at its top and having aninternal tapered pipe thread for securing 'the cap to the upper end ofthe tubular member 30 in an overlapping relationship. A series oforifices 29 are drilled through the tubular section of the cap in aradial direction and having a downwardly inclined axis. The inner upperend 36 of the orifices is open to the interior of the cap so that apassageway is provided for the gas to flow from below the constrictionplate, up the inside of tubular member 30 into the interior of cap 31and then out through orifices 29 above the constriction plate. Thenumber and size of the orifices is selected to obtain the desired volumeof gas flow and the velocity of its stream to best suit the type ofmaterial being fluidized. The axis of inclination of the orifices mayvary, but an angle in the range of 30 to 45 to the horizontal might beconsidered average.

It is to be noted that the cap 31 is easily removed and a cap withdifferent orifice construction may be used to replace the original capto change or improve the per- 1 formance of the individual nozzle. Thevertical projection of the nozzle above the constriction plate 11 may beeasily adjusted up or down by means of the threaded tubular member 30and nut 32 so as to obtain the desired movement of the particles aroundthe base of the nozzle and so that no dead areas exist where materialcan build up and become overheated.

A second embodiment of the nozzle is shown in FIGS. 7 and 8. Nozzle 25comprises a tubular member 40 and a cap member 41. Tubular member 40 hasan external tapered pipe thread 42 on its upper end. Cylindrical holes43, only slightly larger in diameter than the outside diameter oftubular member 40, are punched or drilled in constriction plate 11. Thetubular member is inserted in the hole so that its upper end is at thedesired height above the plate and is welded thereto. It is understoodthat the adjustable threaded means shown in FIG. 6 may also be used insecuring the tubular member 40 to the constriction plate in thisembodiment. Cap member 41 is similar to cap member 31 but in this casethe orifices 44 are not radial. As shown in FIG. 7, the axes of theseorifices are tangent to a small central circle of diameter d as well asbeing downwardly inclined, as shown in FIG. 8. The inner upper end 45 ofthe orifices is open to the interior of cap 41 so that a passageway isprovided for the gas to flow from below the constriction plate 11 up theinside of tubular member 40 into the interior of cap 41 and then outthrough orifices 44 above the constriction plate in a swirling manner sothat thorough distribution of the gas results.

As in the first embodiment, the number and size of orifices 44 in nozzleis selected to obtain the desired volume of gas flow and the velocity ofits stream to best suit the type of material being fluidized. Cap 41 iseasily removed and a cap with different orifice construction may be usedto replace the original cap to change or improve the performance of theindividual nozzle.

Another embodiment of the nozzle of this invention is shown in FIGS. 9and 10. Nozzle 25" comprises a short tubular member 50, a T-shapedfitting 51 and two plugs 52. Tubular member 50 may be a short pipenipple threaded on one end. Cylindrical holes 53, only slightly largerin diameter than the outside diameter of the tubular member 50, arepunched or drilled in constriction plate 11. The tubular member isinserted in a hole 53 so that its upper end is at the desired heightabove the plate and is welded thereto. It is understood that theadjustable threaded means shown in FIG. 6 may also be used for securingthe tubular member 50 to the constriction plate in this embodiment. Athreaded T-shaped fitting 51, such as a pipe tee, is mounted on theupper end of member 50. The two horizontal openings of fitting 51 areprovided with screwed plugs 52 to seal these openings. Radial orifices54 are provided in the lower portions of each of the horizontalextensions of T-shaped fitting 51. As shown in FIG. 10, three suchorifices are indicated, one vertically from the bottom on the centerlineand two at approximately 45 on each side of the vertical centerline. Theinner ends of orifices 54 are open to the interior of T-shaped fitting51 so that passageways for the gas from below the constriction plate areprovided. As in the other embodiments, the number and size of orifices54 are selected to obtain the desired gas flow and the velocity of itsstream to best suit the type of material being fluidized but theorifices should be kept below the horizontal centerline of the T-shapedfitting to prevent entrance of the fine particles in the bed of materialinto the orifices during a shutdown.

Although the best mode contemplated for carrying out the presentinvention has been shown and described herein, it will be apparent thatmodifications and variations may be made without departing from what isregarded the subject matter of the invention.

What I claim is:

l. A nozzle for a fluidized-bed heat transfer apparatus of the typehaving a constriction plate with a plurality of spaced holes in whichthe nozzles are installed, a plenum chamber for the fluidizing gas underthe constriction plate, and a heat transfer chamber above theconstriction plate in which a bed of particulate material is formed, thecombination which comprises:

a. a vertical tubular member mounted in one of the holes of theconstriction plate, said tubular member being adjustable vertically andprojecting above the constriction plate into the bed of material; and

b. a cap member removably attached to the upper end of said tubularmember, said cap member having a closed top portion and a vertical skirtportion depending from said top portion, said skirt being provided witha plurality of orifices controlling the flow of gas, said skirt having avertical wall of sufficient thickness for each of said orifices to forma downwardly inclined passageway connecting the interior of said capmember above the top of said tubular member to a discharge point on theouter surface of said skirt portion, whereby the fluidizing gas can flowunder pressure from below the constriction plate relativelyunrestrictedly through the bore of said vertical tubular member into theinterior of said cap member and then flow controllably downwardly andoutwardly through said plurality of orifices in said cap member touniformly distribute the gas into the bed of particulate materialsurrounding the base of said tubular member to thereby fluidize the bedof particulate material and to prevent buildup of material around thebase of said tubular member.

2. A nozzle for a fluidized bed heat transfer apparatus of the typehaving a constriction plate with a plurality of spaced holes in whichthe nozzles are installed, a plenum chamber under the constriction platewith a source of fluidizing gas under pressure, and a heat transferchamber above the constriction plate in which a bed of particulatematerial is formed, the combination which comprises:

a. a vertical tubular member removably and adjustably mounted in one ofthe holes of said constriction plate and projecting above theconstriction plate into the bed of material, said tubular member havinga relatively unrestricted internal passageway therethrough communicatingwith the plenum chamber; and

b. a cap member removably attached to the upper end of said tubularmember, said cap member having a short annular body portion, a closedtop portion, and pressure tight fastening means for attaching said capmember to said tubular member, said cap member having a plurality oforifices in the periphery of said body portion, said orificescontrolling the flow of fluidizing gas to the bed of particulatematerial, said annular body portion having a vertical wall of sufficientthickness for each of said orifices to form a downwardly inclinedpassageway connecting the interior of said annular body portion abovethe top of said tubular member to a discharge point on the periphery ofsaid body portion, whereby the fluidizing gas can flow unrestrictedlyfrom the plenum chamber through the tubular member into the annular bodyportion of the cap member and then be uniformly distributed through theplurality of inclined orifice passageways in said cap member into thebed of particulate material around the base of the tubular member tothereby fluidize this material and upon stopping the flow of pressurizedfluidizing gas, the inclined passageways prevent the inward flow ofmaterial into the nozzle which might thereby plug the nozzle.

3. In a nozzle for a fluidized bed heat transfer apparatus of the typehaving a constriction plate in which a plurality of the nozzles aremounted, a plenum chamber under the constriction plate with a source offluidizing gas under pressure, and a heat transfer chamber above theconstriction plate in which a bed of particulate material is formed, theimprovement which comprises:

a. a vertical hollow member removably mounted in the constriction plate,the hollow portion of said member providing a relatively unrestrictedcommunicating passage between the plenum chamber and the top of saidhollow member, said hollow member being adjustably mounted in theconstriction plate to vary the projection of the nozzle into the bed ofmaterial above the constriction plate; and

b. a cap member detachably secured to the upper end of said hollowmember, said cap member having an annular body portion, a closed topportion and pressure tight fastening means for securing said cap memberto said hollow member, said body portion having a plurality of orificesproviding a series of passageways from the interior of said body portionabove the top of said hollow member to the outer periphery of said bodyportion, said passageways being inclined downwardly and being orientedradially from the center of said cap member, said annular body portionhaving a sidewall thickness such that the interrelationship between thevertical height of the orifice, the angle of inclination of the orificepassageway and the angle of repose of the particulate material will notpermit the particulate material to flow upwardly throughthe inclinedpassageway and into the interior of the cap member when the flow ofpressurized fluidizing gas is stopped, said orifices further providingfor controlled flow of the fluidizing gas from the interior of said capmember to uniformly distribute the gas into the particulate material tothereby fluidize the bed of material and to prevent buildup of thematerial around the base of said hollow member.

1. A nozzle for a fluidized-bed heat transfer apparatus of the typehaving a constriction plate with a plurality of spaced holes in whichthe nozzles are installed, a plenum chamber for the fluidizing gas underthe constriction plate, and a heat transfer chamber above theconstriction plate in which a bed of particulate material is formed, thecombination which comprises: a. a vertical tubular member mounted in oneof the holes of the constriction plate, said tubular member beingadjustable vertically and projecting above the constriction plate intothe bed of material; and b. a cap member removably attached to the upperend of said tubular member, said cap member having a closed top portionand a vertical skirt portion depending from said top portion, said skirtbeing provided with a plurality of orifices controlling the flow of gas,said skirt having a vertical wall of sufficient thickness for each ofsaid orifices to form a downwardly inclined passageway connecting theinterior of said cap member above the top of said tubular member to adischarge point on the outer surface of said skirt portion, whereby thefluidizing gas can flow under pressure from below the constriction platerelatively unrestrictedly through the bore of said vertical tubularmember into the interior of said cap member and then flow controllablydownwardly and outwardly through said plurality of orifices in said capmember to uniformly distribute the gas into the bed of particulatematerial surrounding the base of said tubular member to thereby fluidizethe bed of particulate material and to prevent buildup of materialaround the base of said tubular member.
 2. A nozzle for a fluidized bedheat transfer apparatus of the type having a constriction plate with aplurality of spaced holes in which the nozzles are installed, a plenumchamber under the constriction plate with a source of fluidizing gasunder pressure, and a heat transfer chamber above the constriction platein which a bed of particulate material is formed, the combination whichcomprises: a. a vertical tubular member removably and adjustably mountedin one of the holes of said constriction plate and projecting above theconstriction plate into the bed of material, said tubular member havinga relatively unrestricted internal passageway therethrough communicatingwith the plenum chamber; and b. a cap member removably attached to theupper end of said tubular member, said cap member having a short annularbody portion, a closed top portion, and pressure tight fastening meansfor attaching said cap member to said tubular member, said cap memberhaving a plurality of orifices in the periphery of said body portion,said Orifices controlling the flow of fluidizing gas to the bed ofparticulate material, said annular body portion having a vertical wallof sufficient thickness for each of said orifices to form a downwardlyinclined passageway connecting the interior of said annular body portionabove the top of said tubular member to a discharge point on theperiphery of said body portion, whereby the fluidizing gas can flowunrestrictedly from the plenum chamber through the tubular member intothe annular body portion of the cap member and then be uniformlydistributed through the plurality of inclined orifice passageways insaid cap member into the bed of particulate material around the base ofthe tubular member to thereby fluidize this material and upon stoppingthe flow of pressurized fluidizing gas, the inclined passageways preventthe inward flow of material into the nozzle which might thereby plug thenozzle.
 3. In a nozzle for a fluidized bed heat transfer apparatus ofthe type having a constriction plate in which a plurality of the nozzlesare mounted, a plenum chamber under the constriction plate with a sourceof fluidizing gas under pressure, and a heat transfer chamber above theconstriction plate in which a bed of particulate material is formed, theimprovement which comprises: a. a vertical hollow member removablymounted in the constriction plate, the hollow portion of said memberproviding a relatively unrestricted communicating passage between theplenum chamber and the top of said hollow member, said hollow memberbeing adjustably mounted in the constriction plate to vary theprojection of the nozzle into the bed of material above the constrictionplate; and b. a cap member detachably secured to the upper end of saidhollow member, said cap member having an annular body portion, a closedtop portion and pressure tight fastening means for securing said capmember to said hollow member, said body portion having a plurality oforifices providing a series of passageways from the interior of saidbody portion above the top of said hollow member to the outer peripheryof said body portion, said passageways being inclined downwardly andbeing oriented radially from the center of said cap member, said annularbody portion having a sidewall thickness such that the interrelationshipbetween the vertical height of the orifice, the angle of inclination ofthe orifice passageway and the angle of repose of the particulatematerial will not permit the particulate material to flow upwardlythrough the inclined passageway and into the interior of the cap memberwhen the flow of pressurized fluidizing gas is stopped, said orificesfurther providing for controlled flow of the fluidizing gas from theinterior of said cap member to uniformly distribute the gas into theparticulate material to thereby fluidize the bed of material and toprevent buildup of the material around the base of said hollow member.